Pressure vessel closure

ABSTRACT

A closure for a pressure vessel that includes a neck with a groove defined in the inner diameter, and a door assembly that pivots between opened and closed positions. The door assembly includes a door portion sized to be received in an opening of the neck, a guide plate connected to the door portion and rotatable between locked and unlocked positions, a first lock ring segment positioned radially outwardly of the guide plate and a handle. The guide plate includes a first cam path defined therein that receives a cam member of a first lug assembly that extends inwardly from the first lock ring segment. Rotation of the handle (and guide plate) from the unlocked to the locked position moves the first lock ring segment from a locked to an unlocked position. In the locked position, the first lock ring segment is received in the groove of the neck.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/697,278, filed Apr. 27, 2015, which claims the benefit of U.S.Provisional Application No. 61/986,024, filed Apr. 29, 2014 theentireties of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to a closure for a pressurevessel.

BACKGROUND OF THE INVENTION

A cost effective apparatus used for a closure in a pressure vessel isneeded for a variety of applications. In the past, when a guided ring isused on a manually operated vessel closure, there is a possibility thatthe operator may inadvertently extend the rings with the door in theopen position. This action creates a potential for damage to occur ifthe operator attempts to close the door while the ring segments areextended. The ring segments make contact with the vessel wall externalsurface which can damage either the ring segments, the vessel wall, orthe guide rods.

Closures which require a high level of machining and/or automation toaccomplish the safe operation of a pressure vessel have been usedfrequently in low volume equipment such as dry cleaning using liquidcarbon dioxide. The apparatus described herein improves on the previousattempts to accomplish the safe closure of pressure vessels.

SUMMARY OF THE PREFERRED EMBODIMENTS

In accordance with an aspect of the present invention there is provideda closure for a pressure vessel that includes a neck that is adapted tobe secured to the pressure vessel and defines a central opening with aninner diameter having a groove defined therein, and a door assembly thatpivots with respect to the neck between an open position and a closedposition. The door assembly includes a door portion that has an innersurface and an outer surface and is sized to be received in the centralopening of the neck, and a guide plate connected to the outer surface ofthe door portion and rotatable between a locked position and an unlockedposition. The guide plate includes at least a first cam path definedtherein, and defines a first axis about which the guide plate rotates.The door assembly also includes a first lock ring segment positionedradially outwardly of the guide plate and including a first lug assemblythat extends inwardly and has a cam member that is received in the firstcam path. Rotation of the guide plate from the unlocked position to thelocked position moves the first lock ring segment from a locked positionto an unlocked position, and, in the locked position, the first lockring segment is received in the groove of the neck. The door assemblyalso includes a handle connected to the guide plate that is movable withthe guide plate between the locked and the unlocked position.

In a preferred embodiment, the neck includes a blocking portionextending therefrom and the handle includes an extension portion thatextends outwardly therefrom. When the door assembly is pivoted from theopen position to the closed position and the handle is in the lockedposition, the extension portion contacts the blocking portion, therebypreventing the door assembly from moving to the closed position.Preferably, the handle comprises a shaft portion that extends in adirection that is generally perpendicular to the first axis, and theextension portion is offset from the shaft portion. The blocking portionincludes a channel defined therein that receives the extension portionwhen the door assembly is in the closed position and the handle isrotated to the locked position. In a preferred embodiment, the firstlock ring segment includes a first guide rod extending inwardlytherefrom that is received in and is translatable through a firstreceiver member that is connected to the door portion. In a preferredembodiment, the first lock ring segment includes a second guide rodextending inwardly therefrom that is received in and is translatablethrough a second receiver member that is connected to the door portion.Preferably, the first and second guide rods are position on oppositesides of the first lug assembly, and the first lug assembly defines anaxis that extends through the first axis and the first and second guiderods each define an axis that does not extend through the first axis.

In a preferred embodiment, the inner surface has a convex shape.Preferably, the guide plate includes an outer diameter and an innerdiameter, the first cam path includes a first end adjacent the outerdiameter of the first cam path and a second end adjacent the innerdiameter of the guide plate, and the first end corresponds to the lockedposition and the second end corresponds to the unlocked position.Preferably, the inner diameter of the neck includes a tapered section.

In accordance with another aspect of the present invention, there isprovided a closure for a pressure vessel that includes a neck having ablocking portion extending therefrom, and a door assembly that pivotswith respect to the neck between an open position and a closed position.The door assembly includes a door portion that includes an inner surfaceand an outer surface and is sized to be received in the central openingof the neck, and a handle that is rotatable between a locked and theunlocked position. The handle includes an extension portion that extendsoutwardly therefrom. When the door assembly is pivoted from the openposition to the closed position and the handle is in the lockedposition, the extension portion contacts the blocking portion, such thatthe door assembly is prevented from moving to the closed position.

In a preferred embodiment, the blocking portion has an arcuate shape andthe handle includes a handle member extending from the shaft portion ina direction that is generally parallel to the first axis. Preferably,the handle is operatively connected to at least one lock ring segment,and rotation of the handle causes the lock ring segment to movelinearly.

One of the functions of the present invention is the use of multiplering segments mounted to the door of the vessel. The rings areassociated with guide rods such that the manual motion of the doorhandle from the unlocked position to the closed and locked positionextends the ring segments into a groove in the vessel wall. Theengagement of the ring segments in the groove of the vessel wallprovides the necessary resistance to the thrust force placed on the doorby the pressure of the vessel contents. A seal mounted on the vesselwall or door provides a means to prevent leaking of the vessel contents.

In a preferred embodiment, the invention also uses an extension on thehandle coupled to the guide plate to prevent the door assembly fromclosing if the ring segments are in the locked position, thus limitingthe potential for accidental operator error and damage to the componentsof the door assembly.

In a preferred embodiment, a further feature of the closure is the useof a single plate with elliptical guide grooves or cam paths. The guideplate has a plurality of grooves which maintain the ring segment guidelugs in the proper position for actuating the ring segments from theopen to the closed (or unlocked and locked) positions and back. Thisguide plate pivots about the center axis of the door when the operatormoves the handle. As the guide plate rotates through its approximately90 degree motion, the elliptical shape of the cam paths impart anangular force of the ring segments which correspond to a radial motionof the ring segments thereby moving the rings in a radial inward andoutward direction.

The ring segments move sufficiently inwardly to allow the door assemblyto disengage from the neck of the vessel wall. A hinge mounted betweenthe door assembly and the vessel external wall provides a pivot pointfor the closure to move from an open to a closed position with the ringsegments positioned to the most inward radial position on the closure.When the door assembly is moved to the closed position, the operator canthen move the door handle in a clockwise direction (or counter clockwisein another embodiment).

The action of moving the handle to the unlocked position (in theclockwise direction) provides two functions. The first function is theclearance of the handle extension to prevent accidental damage to theclosure components, the second is the rotation of the guide plate.

In a preferred embodiment, a two part action is used to move the closurefrom the open access position to the closed and locked or lockedposition. First, the door assembly is moved to the closed position whenthe handle is held generally horizontal and moved about the hinge. Ifthe operator were to attempt to move the door with the handle in aposition other than horizontal, the handle extension would prevent thedoor from reaching the fully closed position as it would hit on theblocking portion. Once the door is fully closed, the handle can then bemoved in a clockwise direction. This action engages the handle with theblocking portion and provides a radial force on the ring segmentsthrough the inclined plane created between the guide plate ellipticalgrooves or cam paths and the guide rods, which moves the ring segmentsto the locked position, and which provides the necessary resistance tothe pressure vessel shear force on the ring segments. It should beunderstood that the handle extension and blocking portion can berearranged such that the handle does not have to be horizontal whenmoving the door to the closed position. The handle can be positioned asdesired around the vessel central opening.

It will be appreciated by those of ordinary skill in the art thatanother benefit of the invention is the seal arrangement between thedoor assembly and the vessel wall. The present invention provides agroove or series of grooves on either the vessel interior wall or theoutside diameter of the door for the addition of a simple seal such asan O-ring or a multiple set of O-rings to seal the internal pressure ofthe vessel during operation. By using a small tapered section in thevessel opening, the door assembly can complete the opening and closingabout the door hinge center point without the need for excess clearance.In other embodiments, this action can be provided by way of a four barlinkage system, straight guide rods mounted axially to the vessel, orany number of methods known to those skilled in the art. However, in apreferred embodiment, by placing an O-ring or a plurality of O-rings inthe vessel opening on a tapered section, the arc created by the swing ofthe door assembly about the hinge is negligible. The mating of the taperof the vessel inside diameter to the door assembly outside diameterprovides a low clearance area to place the vessel seal arrangementwithout the need for elaborate mechanisms.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more readily understood by referring to theaccompanying drawings in which:

FIG. 1 is a perspective view of a pressure vessel closure with the doorassembly in the closed position and with the hinge portions removed inaccordance with a preferred embodiment of the present invention;

FIG. 2 is a perspective view of the pressure vessel closure of FIG. 1with the door assembly in the open position;

FIG. 3 is an exploded view of the pressure vessel closure of FIG. 1;

FIG. 4 is a cross-section of the pressure vessel closure of FIG. 1 withthe lock segments in the locked position;

FIG. 5A is a front elevational view of the pressure vessel closure ofFIG. 1 with the lock segments and guide ring in the open position andwith the hinge portions removed;

FIG. 5B is a front elevational view of the pressure vessel closure ofFIG. 1 with the lock segments and guide ring in the closed position andwith the hinge portions removed; and

FIG. 6 is a top cross-sectional elevational view of the pressure vesselclosure of FIG. 1 with the extension member of the handle contacting theblocking member, thus preventing the door assembly from moving to theclosed position.

Like numerals refer to like parts throughout the several views of thedrawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following description and drawings are illustrative and are not tobe construed as limiting. Numerous specific details are described toprovide a thorough understanding of the disclosure. However, in certaininstances, well-known or conventional details are not described in orderto avoid obscuring the description. References to one or anotherembodiment in the present disclosure can be, but not necessarily are,references to the same embodiment; and, such references mean at leastone of the embodiments.

Reference in this specification to “one embodiment” or “an embodiment”means that a particular feature, structure, or characteristic describedin connection with the embodiment is included in at least one embodimentof the disclosure. Appearances of the phrase “in one embodiment” invarious places in the specification do not necessarily refer to the sameembodiment, nor are separate or alternative embodiments mutuallyexclusive of other embodiments. Moreover, various features are describedwhich may be exhibited by some embodiments and not by others. Similarly,various requirements are described which may be requirements for someembodiments but not other embodiments.

The terms used in this specification generally have their ordinarymeanings in the art, within the context of the disclosure, and in thespecific context where each term is used. Certain terms that are used todescribe the disclosure are discussed below, or elsewhere in thespecification, to provide additional guidance to the practitionerregarding the description of the disclosure. For convenience, certainterms may be highlighted, for example using italics and/or quotationmarks: The use of highlighting has no influence on the scope and meaningof a term; the scope and meaning of a term is the same, in the samecontext, whether or not it is highlighted. It will be appreciated thatthe same thing can be said in more than one way.

Consequently, alternative language and synonyms may be used for any oneor more of the terms discussed herein. Nor is any special significanceto be placed upon whether or not a term is elaborated or discussedherein. Synonyms for certain terms are provided. A recital of one ormore synonyms does not exclude the use of other synonyms. The use ofexamples anywhere in this specification including examples of any termsdiscussed herein is illustrative only, and is not intended to furtherlimit the scope and meaning of the disclosure or of any exemplifiedterm. Likewise, the disclosure is not limited to various embodimentsgiven in this specification.

Without intent to further limit the scope of the disclosure, examples ofinstruments, apparatus, methods and their related results according tothe embodiments of the present disclosure are given below. Note thattitles or subtitles may be used in the examples for convenience of areader, which in no way should limit the scope of the disclosure. Unlessotherwise defined, all technical and scientific terms used herein havethe same meaning as commonly understood by one of ordinary skill in theart to which this disclosure pertains. In the case of conflict, thepresent document, including definitions, will control.

It will be appreciated that terms such as “front,” “back,” “top,”“bottom,” “side,” “short,” “long,” “up,” “down,” and “below” used hereinare merely for ease of description and refer to the orientation of thecomponents as shown in the figures. It should be understood that anyorientation of the components described herein is within the scope ofthe present invention.

FIGS. 1-6 show a closure 10 for a pressure vessel 12 in accordance witha preferred embodiment of the present invention. As shown, in apreferred embodiment, the closure 10 generally includes a neck 14 and adoor assembly 16 that is pivotally connected to the neck 14 or otherportion of the vessel 12. The neck 14 can either be unitary with thevessel 12 or can be secured or otherwise connected to the vessel 12 viaany known method (e.g., welding, mechanical fasteners, adhesive, etc.).The neck 14 defines a central opening 18 that defines an inner diameterhaving a groove 20 defined therein. In another embodiment, the innerdiameter can have a plurality of grooves defined therein.

The door assembly 16 pivots with respect to the neck 14 between an openposition and a closed position. In a preferred embodiment, the doorassembly 16 includes a door portion 22 that includes an inner surface 22a and an outer surface 22 b and that is sized to be received in thecentral opening 18, a guide plate 24, and at least one and preferably aplurality of lock ring segments 26. The guide plate 24 is rotatablysecured to the outer surface 22 b of the door portion 22 such that theguide plate 24 can rotate relative to the door portion 22. Rotation ofthe guide plate 24 can be accomplished in a number of different ways. Inan exemplary embodiment, one or the other of the guide plate 24 and thedoor portion 22 includes a bearing assembly 27. As discussed furtherbelow, the guide plate 24 is rotatable between a locked position and anunlocked position.

As shown in FIG. 3, in a preferred embodiment, the guide plate 24includes at least one and preferably a plurality of cam paths 28 orgrooves defined therein. The cam paths 28 have an arcuate shape having afirst end 28 a adjacent the outer diameter 24 a of the guide plate 24and a second end 28 b adjacent the inner diameter 24 b of the guideplate 24.

The lock ring segments 26 are positioned radially outwardly of the guideplate 24 and each include at least one lug assembly 30 that extendsinwardly (radially) therefrom and that includes a cam member 32 on thedistal end that is received in one of the cam paths 28. In a preferredembodiment the lug assemblies 30 each comprise a push rod 34 and the cammembers 32 are bushings that are secured in an opening 34 a in each pushrod 34 by a nut 36 and bolt 38 arrangement. In another embodiment thecam member can be the shaft of the bolt 38. In another embodiment, thepush rod and cam member can be unitary.

In operation, when the guide plate 24 is rotated, the cam members 32ride along the cam paths 28 thus moving the lock ring segments 26 in aradial direction. In other words, rotational motion of the guide plate24 is converted to radial (linear) motion of the lock ring segments 26by the interaction of the cam paths 28 and cam members 32. Specifically,rotation of the guide plate 24 from the unlocked position to the lockedposition moves the lock ring segments 26 from a locked position to anunlocked position, and vice versa. In the locked position, the lock ringsegments 26 are received in the groove 20 of the neck 14. When the cammembers 32 are positioned at the first end 28 a of the cam paths 28 (seeFIG. 5B) they are in the locked position and when the cam members 32 arepositioned at the second end 28 b of the cam paths 28 (see FIG. 5B),they are in the unlocked position.

In a preferred embodiment, the door assembly 16 also includes at leastone, and preferably a plurality of, guide rods 40 that keep the lockring segments 26 moving in a radial direction when moving inwardly andoutwardly between the locked and unlocked positions. The guide rods 40are each received in an opening defined in a receiver member 41 thatincludes a neck that is attached to the door portion 22 (for example,the neck can be threaded into a female threaded member 39 attached tothe door portion). One end of the guide rods 40 is attached to the innerradial surface of the lock ring segment 26. This can be accomplished bythreading, welding or any other attachment method. In use, as the lockring segment 26 moves inwardly or outwardly, the guide rods 40 moveaxially within the stationary receiver member 41. By having two guiderods 40, the lock ring segment 26 is prevented from twisting. In apreferred embodiment, the lug assembly is position such that it extendsthrough the first axis A1 and the guide rods 40 extend parallel to thepush rod 34, but do not extend through the first axis A1. In anotherembodiment, a flat plate with rollers on each side can be used to guideeach ring segment.

As shown in FIG. 1, the door assembly 16 also includes a handle 42 thatis operatively associated with or connected to the guide plate 24 and ismovable between a locked and unlocked position. The handle 42 can beconnected to the guide plate 24 by any known method, e.g., by mechanicalfasteners 43, welding, adhesive, etc. Any type of handle is within thescope of the present invention as long as it provides the ability torotate the guide plate 24. In a preferred embodiment, the handle 42includes a shaft portion 44 that extends in a direction that isgenerally perpendicular to the axis A1 defined by the guide plate 24, ahandle member 45 extending from the shaft portion 44, and an extensionportion 46 that interacts with a blocking portion 48 extending from theneck 14. As shown in FIGS. 1 and 5B, when the handle 42 is moved to thelocked position (and the door assembly 16 is in the closed position),the extension portion 46 is received in a channel 50 defined by theblocking portion 48. However, as shown in FIG. 6, if the door assembly16 is moved from the open position toward the closed position while thehandle 42 is in the locked position, the extension portion 46 willcontact the blocking portion 48, thereby preventing the door assembly 16from reaching the closed position. This prevents the lock ring segments26 from hitting the neck 14 and possibly damaging the lock ring segments26, the lug assemblies 30 or any other components. In anotherembodiment, the handle can be circular or the handle can simply be a rodthat extends outwardly from the guide plate 24.

As shown in FIGS. 2-3, in a preferred embodiment, the door assembly 16is pivotal with respect to the vessel 12 by a hinge 52. Any type ofhinge is within the scope of the present invention. In a preferredembodiment, the hinge 52 includes a hinge portion 54 that is attached tothe door portion 22 and a hinge portion 56 that is attached to thevessel 12. The hinge portions 54 and 56 include complementary knuckles58 and barrels 60 through which a hinge pin 62 extends. Preferably,hinge portion 54 includes a curved cut out 64 therein that providesclearance for some of the moving components of the door assembly 16 andincludes openings 66 therein that provide connection to the door portion22 via studs 68 or the like. Hinge portion 54 can be connected to doorportion 22 by any known method, e.g., welding, mechanical fasteners,adhesives, etc.

As shown in FIGS. 2 and 4, in a preferred embodiment, the inner surface22 a of the door portion 22 has a convex shape. Preferably, the outersurface 22 b has a concave shape, which defines a space that at leastpartially receives the guide plate 24 and related components. The convexinner surface 22 a abuts a basket 70 inside the vessel. The basket 70includes an outer flange 72 that defines an opening 74 into which theconvex inner surface 22 a extends.

In a preferred embodiment, one or both of the neck 14 and the doorportion 22 includes a seal 76 to prevent leaking of the vessel contents.As shown in FIG. 4, in a preferred embodiment, the seal 76 is mounted onthe door portion 22. The present invention provides a groove 78 orseries of grooves on the outside diameter of the door portion 22 formounting of the seal 76 (such as an O-ring or a multiple set of O-rings)to seal the internal pressure of the vessel during operation. In apreferred embodiment, the neck 14 includes a tapered section 80 in thevessel opening, which allows the door assembly 16 to complete theopening and closing about the door hinge 52 center point without theneed for excess clearance. It will be appreciated that by placing theseal 76 in the opening 18 on the tapered section 80, the arc created bythe swing of the door assembly 16 about the hinge is negligible. Themating of the taper of the vessel inside diameter to the door assemblyoutside diameter provides a low clearance area to place the vessel sealarrangement.

The lock ring segments 26 are shown in the closed position in FIG. 5B.As shown, the guide plate 24 and handle 42 are positioned fullyclockwise with the handle 42 held in the groove of the blocking portion48. FIG. 5A shows the lock ring segments 26 in the open position. Asshown, the guide plate 24 and handle 42 are in the fullcounter-clockwise position. The handle 42 is beyond the blocking portion48, which allows the operator to swing the door assembly to the openposition providing access to the interior of the pressure vessel 12.

In use, when the door assembly 16 is in the closed position, as shown inFIG. 5B, to unlock and open the door assembly 16, the handle 42 is movedfrom the locked position (FIG. 5B), where the extension member 46 isreceived in the channel 50 of the blocking portion 48, to the unlockedposition (FIG. 5A), where the extension member 46 is outside of thechannel 50 of the blocking portion 48. This motion rotates the guideplate 24 from the locked position (FIG. 5B) to the unlocked position(FIG. 5A). This motion causes the cam member 32 to ride along the campaths 28 from the locked position (FIG. 5B) to the unlocked position(FIG. 5A). This motion causes the push rods 34 to pull the lock ringsegments 26 inwardly from the locked position (FIG. 5B) to the unlockedposition (FIG. 5A) and out of the groove 20. While this happens, theguide rods 40 translate within the receiver members 41 to guide the lockring segments 41 in a radial direction. At this point, the door assembly16 can be pivoted from the closed position (FIG. 5A) to the openposition (FIG. 2).

In use, when the door assembly 16 is in the open position, as shown inFIG. 2, to close and lock the door assembly 16, the operator pivots thedoor from the open position to the closed position (FIG. 5A). Next, thehandle 42 is moved from the unlocked position (FIG. 5A), where theextension member 46 is outside of the channel 50 of the blocking portion48, to the locked position (FIG. 5B), where the extension member 46 isreceived in the channel 50 of the blocking portion 48. This motionrotates the guide plate 24 from the unlocked position (FIG. 5A) to thelocked position (FIG. 5B). This motion causes the cam member 32 to ridealong the cam paths 28 from the unlocked position (FIG. 5A) to thelocked position (FIG. 5B). This motion causes the push rods 34 to pushthe lock ring segments 26 outwardly from the unlocked position (FIG. 5A)to the locked position (FIG. 5B) and in the groove 20. While thishappens, the guide rods 40 translate within the receiver members 41 toguide the lock ring segments 41 in a radial direction.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” As used herein, the terms “connected,”“coupled,” or any variant thereof, means any connection or coupling,either direct or indirect, between two or more elements; the coupling ofconnection between the elements can be physical, logical, or acombination thereof. Additionally, the words “herein,” “above,” “below,”and words of similar import, when used in this application, shall referto this application as a whole and not to any particular portions ofthis application. Where the context permits, words in the above DetailedDescription of the Preferred Embodiments using the singular or pluralnumber may also include the plural or singular number respectively. Theword “or” in reference to a list of two or more items, covers all of thefollowing interpretations of the word: any of the items in the list, allof the items in the list, and any combination of the items in the list.

The above-detailed description of embodiments of the disclosure is notintended to be exhaustive or to limit the teachings to the precise formdisclosed above. While specific embodiments of and examples for thedisclosure are described above for illustrative purposes, variousequivalent modifications are possible within the scope of thedisclosure, as those skilled in the relevant art will recognize.Further, any specific numbers noted herein are only examples:alternative implementations may employ differing values, measurements orranges. It will be appreciated that any dimensions given herein are onlyexamplary and that none of the dimensions or descriptions are limitingon the present invention.

The teachings of the disclosure provided herein can be applied to othersystems, not necessarily the system described above. The elements andacts of the various embodiments described above can be combined toprovide further embodiments.

Any patents and applications and other references noted above, includingany that may be listed in accompanying filing papers, are incorporatedherein by reference in their entirety. Aspects of the disclosure can bemodified, if necessary, to employ the systems, functions, and conceptsof the various references described above to provide yet furtherembodiments of the disclosure.

These and other changes can be made to the disclosure in light of theabove Detailed Description of the Preferred Embodiments. While the abovedescription describes certain embodiments of the disclosure, anddescribes the best mode contemplated, no matter how detailed the aboveappears in text, the teachings can be practiced in many ways. Details ofthe system may vary considerably in its implementation details, whilestill being encompassed by the subject matter disclosed herein. As notedabove, particular terminology used when describing certain features oraspects of the disclosure should not be taken to imply that theterminology is being redefined herein to be restricted to any specificcharacteristics, features or aspects of the disclosure with which thatterminology is associated. In general, the terms used in the followingclaims should not be construed to limit the disclosures to the specificembodiments disclosed in the specification unless the above DetailedDescription of the Preferred Embodiments section explicitly defines suchterms. Accordingly, the actual scope of the disclosure encompasses notonly the disclosed embodiments, but also all equivalent ways ofpracticing or implementing the disclosure under the claims.

Accordingly, although exemplary embodiments of the invention have beenshown and described, it is to be understood that all the terms usedherein are descriptive rather than limiting, and that many changes,modifications, and substitutions may be made by one having ordinaryskill in the art without departing from the spirit and scope of theinvention.

What is claimed is:
 1. A closure for a pressure vessel, the closure comprising: a neck that is adapted to be secured to the pressure vessel, wherein the neck defines a central opening that defines an inner diameter, and wherein a groove is defined in the inner diameter, a door assembly that pivots with respect to the neck between an open position and a closed position, wherein the door assembly includes a door portion that includes an inner surface and an outer surface, wherein the door portion is sized to be received in the central opening of the neck, a guide plate that is co-axial with and connected to the door portion, wherein the guide plate is rotatable between a locked position and an unlocked position, wherein the guide plate includes at least a first cam path defined therein, wherein the guide plate defines a rotation plane and a first axis about which the guide plate rotates, and wherein the cam path is defined in the rotation plane, a first lock ring segment positioned radially outwardly of the guide plate and including a first lug assembly that extends inwardly and has a cam member that is received in the first cam path, wherein rotation of the guide plate from the unlocked position to the locked position moves the first lock ring segment from a locked position to an unlocked position, and wherein in the locked position, the first lock ring segment is received in the groove of the neck, and a handle connected to the guide plate that is movable with the guide plate between the locked and the unlocked position.
 2. The closure of claim 1 wherein the neck includes a blocking portion extending therefrom, wherein the handle includes an extension portion that extends outwardly therefrom, wherein when the door assembly is pivoted from the open position to the closed position and the handle is in the locked position, the extension portion contacts the blocking portion, such that the door assembly is prevented from moving to the closed position.
 3. The closure of claim 2 wherein the handle comprises a shaft portion that extends in a direction that is generally perpendicular to the first axis, wherein the extension portion is offset from the shaft portion in a direction that is generally parallel to the first axis, wherein the blocking portion includes a channel defined therein that receives the extension portion when the door assembly is in the closed position and the handle is rotated to the locked position.
 4. The closure of claim 1 wherein the first lock ring segment includes a first guide rod extending inwardly therefrom that is received in and is translatable through a first receiver member that is connected to the door portion.
 5. The closure of claim 4 wherein the first lock ring segment includes a second guide rod extending inwardly therefrom that is received in and is translatable through a second receiver member that is connected to the door portion.
 6. The closure of claim 5 wherein the first and second guide rods are position on opposite sides of the first lug assembly, and wherein the first lug assembly defines an axis that extends through the first axis and the first and second guide rods each define an axis that does not extend through the first axis.
 7. The closure of claim 1 wherein the inner surface has a convex shape.
 8. The closure of claim 1 wherein the guide plate includes an outer diameter and an inner diameter, wherein the first cam path includes a first end adjacent the outer diameter of the first cam path and a second end adjacent the inner diameter of the guide plate, and wherein the first end corresponds to the locked position and the second end corresponds to the unlocked position.
 9. The closure of claim 1 wherein the inner diameter of the neck includes a tapered section.
 10. The closure of claim 1 wherein the guide plate is movable with the door portion between the open and the closed position.
 11. The closure of claim 11 wherein the guide plate is mounted on the outer surface of the door portion.
 12. A closure for a pressure vessel, the closure comprising: a neck that is adapted to be secured to the pressure vessel, wherein the neck includes a front surface and defines a central opening that defines an inner diameter, and wherein a groove is defined in the inner diameter, wherein the neck includes a blocking portion having an inner surface and an outer surface extending therefrom, wherein the outer surface of the blocking portion is positioned axially outwardly from the front surface of the neck and the groove is positioned axially inwardly from the front surface of the neck, a door assembly that pivots with respect to the neck between an open position and a closed position, wherein the door assembly includes a door portion that includes an inner surface and an outer surface, wherein the door portion is sized to be received in the central opening of the neck, and a handle that is rotatable about a first axis between a locked and the unlocked position, wherein the handle is movable with the door portion between the open and the closed position, wherein the handle includes an extension portion that extends outwardly therefrom, wherein the blocking portion has an arcuate shape and is co-axial with the first axis, wherein when the door assembly is pivoted from the open position to the closed position and the handle is in the locked position, the extension portion contacts the outer surface of the blocking portion, such that the door assembly is prevented from moving to the closed position.
 13. The closure of claim 12 wherein the handle comprises a shaft portion that extends in a direction that is generally perpendicular to the first axis, wherein the extension portion is offset from the shaft portion in a direction that is generally parallel to the first axis, wherein the blocking portion includes a channel defined therein that receives the extension portion when the door assembly is in the closed position and the handle is in the locked position.
 14. The closure of claim 13 wherein the handle includes a handle member extending from the shaft portion in a direction that is generally parallel to the first axis.
 15. The closure of claim 13 wherein the handle is operatively connected to at least one lock ring segment, such that rotation of the handle causes the lock ring segment to move linearly.
 16. The closure of claim 12 wherein the handle rotates about a first axis, and wherein the handle moves in a plane that is generally perpendicular to the first axis.
 17. The closure of claim 16 wherein the neck defines a second axis, wherein when the door assembly is in the closed position the second axis is co-axial with the first axis, and wherein when the extension portion contacts the outside surface of the blocking portion the second axis is not co-axial with the first axis.
 18. The closure of claim 10 wherein the blocking portion includes a channel defined therein, and wherein the channel is located axially outwardly from the front surface of the neck. 